docs: def _compute_fluxes(self):
          """
          Compute integrated flux inside ellipse, as well as inside a
          circle defined with the same semimajor axis.
  
          Pixels in a square section enclosing circle are scanned; the
          distance of each pixel to the isophote center is compared both
          with the semimajor axis length and with the length of the
          ellipse radius vector, and integrals are updated if the pixel
          distance is smaller.
          """
  
          # Compute limits of square array that encloses circle.
          sma = self.sample.geometry.sma
          x0 = self.sample.geometry.x0
          y0 = self.sample.geometry.y0
          xsize = self.sample.image.shape[1]
          ysize = self.sample.image.shape[0]
  
          imin = max(0, int(x0 - sma - 0.5) - 1)
          jmin = max(0, int(y0 - sma - 0.5) - 1)
          imax = min(xsize, int(x0 + sma + 0.5) + 1)
          jmax = min(ysize, int(y0 + sma + 0.5) + 1)
  
          # Integrate
          if (jmax-jmin > 1) and (imax-imin) > 1:
              y, x = np.mgrid[jmin:jmax, imin:imax]
              radius, angle = self.sample.geometry.to_polar(x, y)
              radius_e = self.sample.geometry.radius(angle)
  
              midx = (radius <= sma)
              values = self.sample.image[y[midx], x[midx]]
              tflux_c = np.ma.sum(values)
              npix_c = np.ma.count(values)
  
              midx2 = (radius <= radius_e)
              values = self.sample.image[y[midx2], x[midx2]]
              tflux_e = np.ma.sum(values)
              npix_e = np.ma.count(values)
          else:
              tflux_e = 0.
              tflux_c = 0.
              npix_e = 0
              npix_c = 0
  
          return tflux_e, tflux_c, npix_e, npix_c